The
Boise and Snake River Valleys are major waterfowl wintering areas in the Pacific
Flyway. Lake Lowell provides roosting and feeding habitat for large
numbers of migrating and wintering waterfowl, primarily mallards and Canada
geese. Upland game birds are common to the refuge and include ring-necked
pheasant and California quail. The majority of past study and monitoring on
the refuge has focused on waterfowl and other game birds. Informal surveys
were conducted in mid-June of 1998 within each of the major habitat types
at Lake Lowell for breeding birds, resident mammals, amphibians, and reptiles.
Surveys for breeding birds were conducted in 4 distinct habitat types:
Russian Olive-fringed Marsh; Shrub-steppe Uplands; Cottonwood Forest; and
Willow/Shrub Uplands. During June and July of 1998, field surveys for
amphibians and reptiles were conducted. A list was compiled of birds
and amphibians detected in each of the habitat types. Through
incidental observations, tracks and other signs, a list of mammals was created.
The potential affects on wildlife from the management actions proposed by
the US Bureau of Reclamation to improve water quality was discussed in this
report. The effects vary depending on the habitat type. Habitat
for breeding birds in the Russian Olive-fringed Marsh and Shrub Steppe
Upland could likely be improved by management of exotic vegetation and introduction
of more native plant species. The Cottonwood habitat on the south side
of Lake Lowell could be greatly affected by management actions that
manipulate the lake water levels. If cottonwoods were dry during spring
breeding season, this could allow for understory willow growth and other upland
vegetation. This would improve habitat for breeding songbirds, but it
is unknown how it may affect breeding birds in the existing habitat. Amphibians
could be directly affected by management actions designed to improve water
quality. Manipulation of lake water levels during the breeding season
could result in stranding of amphibian eggs. Because
amphibians respire through their moist skins, they could be directly affected
by contaminants in lake water or sediments. Improving water quality
within the refuge should benefit native amphibians in the long run.
It is unlikely that proposed management actions would affect resident reptile
species. Most reptiles live in upland habitats removed from the lake
or its associated wetlands, and are thus not likely to be directly affected
by high contaminant levels. The study recommends that more extensive and detailed
surveys be conducted of wildlife, and the use of GIS technology to determine
the exact amounts of specific habitats. Also, a detailed evaluation
of contaminants within Lake Lowell sediments should be made to determine the
extent of contamination possible to migrating shorebirds and other wildlife.